A heat-treatment apparatus is known, for example from my German published patent application No. 2,810,178, wherein a textile web is loaded onto the upstream end of an upper stretch of a gas-pervious conveyor belt that passes through a heat-treatment chamber. Upwardly directed lower nozzles below the belt and downwardly directed upper nozzles above the belt are alternately fed hot air under pressure to heat treat the web and simultaneously move it on the belt. To allow the web to move, it is fed loosely onto the belt by being deposited thereon at a speed substantially greater than the belt-advance speed. Such treatment not only dries the web, but also normally improves its hand and preshrinks it.
The upper nozzles are formed by a multiplicity of small evenly spaced perforations in an upper wall and the lower nozzles are elongated transverse to the path and are formed by slots in distribution and support boxes underneath the belt. As a result there is an extremely even and gentle flow of air, so that the web is treated quite gently. Although this gentle treatment is normally considered a plus of the system, especially when applied to natural fibers, it has been found that it imparts shine to many synthetics. In particular synthetic textiles with a pile extending warpwise of the goods are frequently rendered quite shiny. As a result blankets or the like made of such pile have a fake look that makes them unable to compete with blankets made of natural fibers.